Power over Ethernet (PoE) technology describes passing electrical power, along with data, on Ethernet cabling. It is regulated by the IEEE 802.3at-2009 standard. Power is supplied in common mode over two or more of the differential pairs of wires found in the Ethernet cables and comes from a power supply within a PoE-enabled networking device such as an Ethernet switch, or can be injected into a cable run with a midspan power supply. The basic elements of a PoE system are: 1) Power Sourcing Equipment (PSE): a device such as a switch that provides (“sources”) power on the Ethernet cable, and 2) a Powered Device (PD) powered by a PSE that consumes energy from the PSE. Examples of powered devices include wireless access points, Internet Protocol (IP) telephones, and IP cameras.